149 



however, express the very greatest respect. There is no tra( e 

 in those I obtained from the LimnodriUis of any distinct cuticle, 

 of any contractile vesicle, nor of a nucleus-like structure ; 

 neither does the dense hair-like fringe exhibit any movement 

 like that of cilia, though I watched the supposed organism 

 when within the spermatic sac. M. Claparede observed languid 

 ciliary movements when the Pachydermon was placed in 

 salt water, which is not what we should expect in the case 

 of an Opalina. On the contrary, I think these remarkable 

 structures must be regarded as spermatophors — aggregations 

 of spermatozoa, perhaps cemented and worked into this shape 

 through the secretion and action of the spermatic sac. The 

 (lotted appearance of the central portion of the spermatophor 

 is caused by the aggregated heads of the individual sperma- 

 tozoa ; whilst the dense fringe is due to their pendant and 

 interwoven filaments. As indicated in the drawing, the 

 filaments do not all stand out in one direction from the more 

 central portion of the mass, but are crossed and interwoven, 

 a circumstance which is not indicated in M. Claparede's 

 figures of Pachydermon. 



If one of these masses be broken by pressure, very con- 

 clusive evidence is obtained that we have not to do with an 

 Infusorian, but that the mass is composed of aggregated 

 filaments such as spermatozoa. No cuticle is ruptured by 

 the pressure, and no differentiation of the supposed sarcodic 

 material is disclosed, but simply a felted structure, composed 

 of innumerable filaments. In fact, everything that I was 

 able to ascertain with regard to these bodies tended to 

 show that they Avere simply masses of spermatozoa woven 

 together and agglutinated in that very remarkable manner 

 in which Ave know spermatophors are produced in other 

 cases. Spermatophors have been described in the Polycha3ta 

 (by M. Claparede himself), and hence w^e may fairly ex- 

 pect them in the Oligocheeta. 



M. Jules d'Udekem regarded the bodies Avhich he observed 

 as connected Avith the formation of the egg-capsule, having 

 mistaken the spermatic reservoirs for an egg-capsale secreting 

 gland. Similarly he described long filaments in the sper- 

 matic reservoirs of Stylaria, as destined to strengthen the 

 egg-capsule of that Naid. 



In the spring (of 1869) I made some careful studies of the 

 genital organs of Nais serpentina ; and in the enormous 

 spermatic reservoirs Avhich dcA^elop in that Annelid at a late 

 period of its sexual history, I found long coiling filaments, 

 having a fibrous structure (figs. 11, 12), These, no doubt, 

 are identical Avith the filaments seen by d'Udekem in Stylaria, 



A'OL. IX. NEW SER. L 



